Tuning mechanism for radio receiving apparatus



m 1936- E. A. ZADIG 9 TUNING MECHANISM FOR RADIO RECEIVING APPARATUSFiled July 10, 1929' 2 Sheets-Sheet l I 14 m/v/n/6 I) fiEJ TORS gINVENTOR M W 7% W ATTORNE April 21, 33% A ZADIQ 2,3@,Z57

TUNING MECHANISM FOR RADIO RECEIVING APPARATUS Filed July 10, 1929 2Sheets-Sheet 2 INVENTOR: W

ATTORN EY Patented Apr. 21

UNITED STATES TUNING MECHANISM FOR RADIO RECEIVING APPARATUS Ernest A.Zadig, New York, N. Y., assignor to Radio Corporation of America,

New York,

N. Y., a corporation of Delaware Application July 10, 1929, Serial No.377,151

14 Claims.

This invention relates to apparatus for tuning radio receiving devicesand more particularly to apparatus for tuning radio receiving devicesfrom a remote point.

Heretofore in the operation of radio receiving devices, it has beencustomary to tune the same by the manipulation of dials, etc.,- locatedabout or secured to the casing containing the receiving device andconnected to the tuning elements of the receiver. In some instances, itis desirable that the actual receiving apparatus be located at a pointremote from the listener and for this purpose it is desirable that somearrangement be provided for tuning this receiving device withoutrecourse toactual manipulation of the dials secured to the set.

Accordingly, an object of the present invention is to provide means fortuning a radio receiving set from a remote point.

The present invention provides an arrangement whereby a radio receivingset can be tuned from any point however remote from the actual set thelistener may be. The apparatus for accomplishing this purpose consistsin a source of motive power for tuning the various apparatus to be movedduring the tuning operation, which source of motive power is adapted tobe controlled from any outside point. In perfecting this control, use ismade ofv the usual interrupter type signaling device commonly used inconnection with automatic telephones.

Other features and objects of the invention will become apparent byreference to the following detailed description taken in connection withthe accompanying drawings wherein Figure l is a perspective schematicview of a radio receiving device enclosed in a cabinet and havingconnected thereto the impulse generator through the agency of whichtuning is accomplished;

Fig. 2 is an elevation of the source of motive power utilized in tuningthe apparatus and the controlling mechanism thereto;

Fig. 3 is a plan view of the same device illustrated in Fig. 2;

.Fig. 4 is an enlarged view of the arrangement shown in Fig. 3;

Fig. 5 is an enlarged perspective view of the dial showing thecalibrations thereon and the mechanism for controlling the source ofmotive power; and

Fig. 6 is a perspective view of one of the lugs attached to thecalibrated dial.

Referring now to the drawings, It! indicates the cabinet of a radioreceiving device of any desired character having the usual tuning knob Hand dial I2 which is calibrated for aiding in tuning the apparatus tothe desired wave length. Inasmuch as the actual mechanism employed inthe receiving device forms no part of the invention, it is notillustrated here in detail.

In Fig. 1, [3 indicates a device for causing interruptions in a closedcircuit, such device being of the type commonly used in connection withautomatic telephones. Inasmuch as these devices are well known in theart, the same is not described or illustrated in detail. Suffice it tosay that upon movement of the dial in a counterclockwise direction, thecircuit connected therewith is opened and closed a number of timescorresponding to the distance traveled by the dial. In the presentinstance, the member I3 is shown connected to the receiving apparatusthrough a pair of lines l4. Passage of current through lines i4 anddevice I3 is controlled by switch 5%] and indicated by pilot light 5i.If desired current for operating the set may be controlled by switch inthe same manner.

Mounted within the casing ID at any desired place is a source of motivepower; in the present instance, an electric motor 15 which is geared tothe shaft it, upon which the dial I2 is frictionally mounted, throughreduction gears I1 and 18. By, the use of these reduction gears, it ispossible when the motor i5 is energized to turn the shaft 16, whichshaft l6 serves as a common shaft for the apparatus utilized in tuningthis receiving device. This apparatus may be a train of condensers orany other type of mechanism desired, and is represented diagrammaticallyin Fig. 1 and labeled tuning reactors.

Secured to the dial l2 at spaced intervals are a number of lugs I9 whichextend therefrom an even distance. Depending from each of these lugs I9is a trip member 26 spaced at different intervals from the ends of therespective lugs. The necessity for this spacing will be apparenthereinafter, but it should be noted that they serve to control theapparatus for different stations. The lugs l9 will be secured to thedial H at points thereupon which correspond to the points at whichdifferent broadcasting stations are usually received,

Secured within the casing H1 in any convenient place (in the presentinstance, on the motor casing H3) is a selector member 2| in the shapeof a bar slidable between two guide members 22 and 23. In the presentinstance, this bar 2| is of square shape though it may be rectangular orany shape desired.

Extending centrally through the bar 2| is a rotatable shaft 24 fromwhich extends an arm 25 through an opening near one end of bar 2|. Nearthe other end of the bar 2| is a second opening which permits thesecuring to the shaft 24 of a crank 26, the latter preferably beingshown as integral with shaft 24, an arm 21 extending through a slot in apawl member 28. The arm 21 is pivoted at one end thereof to crank 26,and its other end is free to move horizontally in a backward and forwardmanner in the slot, a knob 21' on the end thereof preventing withdrawalfrom the slot. One side of bar 2| is cut away to provide a rack 29 madeup of a number of teeth.

Mounted adjacent to the bar 2| is an electromagnet 30 having core 3|.Pivoted above core 3| is an arm 32, the end 32a of which serves as apawl member for advancing the bar 2| through the guides 22 and 23. Thisarm 32 is forced normally toward the dial |2 by means of a spring 33,its movement in this direction being limited by a stop 34. The pawlmember 28 previously referred to has an angular extension 35 which, dueto the fact that the member is pivoted about the point 38, can be forcedinto engagement with the teeth of rack 29 by means of the spring 31pressing against the upper end of member 28.

Pivoted to the rear of member 28 and about the point 38 is a switch bar39 provided with a contact point 40 co-operating with a contact 4| tocontrol the circuit of motor l5. This contact bar 39 is normally forcedtoward a position to close the contacts 40 and 4| by means of a spring42. The end of the bar 39 remote from contact 40 is provided with a camshoulder 43 against which the end 28 of member 28 is adapted to presswhen the same is rotated about its pivot. A second switch composed ofcontact members 52 and 53 controls the flow of current either to theentire set or only to the loud speaking instrument as desired. Thisswitch is normally closed, being opened only during mechanical tuning.

A stop 44 secured to bar 2| and against which the end of bar 39 restsserves to prevent the closing of contacts 40 and 4| when the bar 2| isin its position most remote from the dial 2. Spring 45, one end of whichis secured to stop 44 and the other end of which is secured to guide 23at the point 46, serves to withdraw the bar 2| from dial l2.

Having described the mechanism embodied in the invention, the operationof the same is substantially as follows:

The set will be tuned manually, that is, the apparatus associated withthe dial l2 will be moved to a proper position corresponding to thestation from which broadcast waves are to be received. With theapparatus and dial |2 in the proper tuned position one of the lugs withits trip secured thereto will be fastened to the dial at the properstation number. The lug may be inserted through the opening 54 in theplate secured to the front of the cabinet and then fastened to the dialin any desired manner such as by means of small set screw. This manualtuning of course is made possible due to the fact that the motor drivefor the dial and associated apparatus is a frictional drive.

After lugs have been fastened to the dial in positions corresponding tothe points thereof at which different broadcast waves are received theset is in condition to be tuned mechanically.

Each of the lugs I9 is provided with a trip 20 which is spaced atvarying distances from the ends of the lugs. For example, the lug 9which in Fig. 5 is shown approximately opposite the number 20 on thedial I2, is provided with trip member 20 near the free end thereof. Thenext lug approximately opposite the number 30 is provided with a trip 28which is a slight distance closer to the dial than the preceding tripand so on around the dial.

Current for operating the set may be supplied thereto from any desiredsource, the supply being controlled by switch 50. As soon as the circuitfrom the source to the set is closed through this switch the same willbe indicated by the pilot light 5| which indicates that the magnet 39 isenergized rendering the mechanical tuning equipment in condition foroperation.

With the interrupter l3 connected in the circuit of the electromagnet30, which is normally energized, impulses or interruptions of the flowof current through the magnet can be produced by rotation of the dial ofthis interrupter. For example, should it be desired to tune in a stationfor which the dial I2 is normally turned until the indicator on the setreaches the point 40, the interrupter l3 will be operated by placing apencil or other similar device in the opening numbered 3, rotating thedial clockwise to the stop, and releasing the same. As the dial rotatescounter-clockwise, three interruptions in the current flowing throughelectromagnet 30 will be produced. When the circuit is broken,denergizing the magnet, the spring 33 pulls arm 32 in the direction ofthe dial. As this arm moves towards the dial and before it reaches stop34, it engages one tooth of rack 29 and moves it and the bar 2| towardthe dial l2. As soon as the circuit is completed again, the bar 32 isattracted again to the magnet, but the bar 2| is held in this advancedposition by engagement of the point 35 with one of the teeth of rack 29.The succeeding impulses or interruptions in current flow through themagnet cause the advancement of bar 2| a distance corresponding to thenumber of teeth advanced by pawl 32. In the example of thisillustration, the number of teeth by which the bar 2| will be advancedis three. As soon as bar 2| moves from its normal position, spring 42forces bar 39 about its pivotal point and contacts 40 and 4| are closed,thereby energizing the m0- tor 5, which upon rotation moves the dial l2and the apparatus associated therewith. Simultaneously with the closingof contacts 40 and 4| contacts 52 and 53 are opened breaking the powercircuit to the entire set or to the loud speaker as the case may be forthe purpose of preventing confusing signals being received as the set istuned through undesired broadcasting bands.

This rotation of the dial continues (due to the motor l5) until arm 25has moved into the path of the trip 20 secured to the lug 9 oppositenumber 40. When the arm 25 comes into contact with the trip 20 and themotor l5 causes continued rotation of dial l2, the arm 25 is forced tofollow this rotation somewhat due to the length of the finger portion25', thereby imparting a slight rotary movement to the shaft 24 to whichthe arm is secured. Upon rotation of the shaft 24, the member 28 isrotated about its pivotal point due to the crank 26, arm 21 of which hasbeen moving upwardly along member 28 through the slot provided therein.Rotation of this member 28 produces two instantaneous results, one ofwhich is to release point 35 from contact with the teeth of rack 29,thereby permitting the spring 45 to retract bar 2|, and the other resultof which is to cause the end of member 28 to ride up shoulder 43. of bar39, depressing the same and opening the motor switch, through contacts40 and 4 I. More particularly this operation may be explained asfollows: A trip 20 is intercepted by the finger of arm 25, the shaft 24is angularly displaced thus moving the link 21 backward and rotating thedog about the pivot 28. This results in the raising of dog 35 and thelowering of the edge 28' into that position wherein it is prevented fromreturning to its spring pressed normal position by the abutment 43. Itremains in this position until the spring has retracted the bar 2| andrack 29 to its normal position prior to dialing operation, at whichnormal position the pin 44 strikes the portion of the switch 39 in itspath, and releases the edge 28, thereby permitting the spring 31 topress the dog 35 into contact with the rack 29, thus preparing theentire mechanism for a complete renewal of the cycle or" operation.

As shown in Figs. 2 and 3 particularly, the position of the mechanism isshown at the instant when the entire cycle has been completed, after thepin 44 has released the edge 28' from the abutment 43, and has made themechanism receptive for a new dialing operation. Naturally, when thesecontacts 4'0, M are opened, the dial I2 is no longer rotated and theapparatus of the receiving device stays at the point of tuning desired.The controlling mechanism having been returned to its normal position,the set may be tuned for any other station desired by manipulating theinterrupter i3 in the manner before explained.

In the event the dial l2 and the tuning apparatus associated therewithare not rotatable through 360 but only through 180 switches may beprovided at diametrically opposite points for reversing the direction ofrotation of the motor. For actuating these switches (which are notillustrated) use may be made of a trip member 55 located upon andsecured to the inner face of the dial Hi. It will be evident that theoperation of this arrangement is: The dial and associated mechanism willbe rotated until the proper point is reached even though it may benecessary to reverse the direction of movement due to the fact that thedial has already rotated past the point of desired reception.

It is to be understood that the present invention is not to be limitedto the embodiment illustrated, but is to be limited only by the appendedclaims.

I claim:

l. The combination with the tuning elements of a radio receiving systemof a driven member associated therewith, a source of electromotive powerfor driving said member, selective control mechanism for said sourceactivated by interruptions in current flow therethrough, meansresponsive to adjustment of the driven member to a predeterminedposition, for actuating the control mechanism to render the sourceinoperative at said position, and means for causing interrupt tions incurrent flow through said control mechanism.

2. Means for tuning a radio receiver comprising the combination of ashaft, a plurality of tuning reactors mounted thereon, a drum memberassociated therewith and having a number of trip members secured aboutthe periphery thereof at different positions, a source of electromotivepower for driving said member, a control member for said source having apart movable into the paths of said trip members, and. means forselectively causing the advancement of said part into the path of apredetermined one of said trip members to actuate the control member torender the source inoperative.

3. The combination with the tuning reactors of a radio receiving systemof a driven member associated therewith and having a number of tripmembers secured thereto at different positions, at least two of saidtrip members having securing means arranged so that they may beangularly adjusted about the periphery of said member, and a source ofelectromotive power for driving said member, a control member for saidsource having a part movable into the paths of said trip members, meansfor selectively causing the advancement of said part into the path of apredetermined one of said trip members, and means operable upon contactof said part with one of said trip members to cause deenergization ofsaid source and for returning said part to normal position.

4. In combination, a radio receiving set, a station selector remote fromthe set, means for tuning the set to a desired station, a motor actuatedmeans for varying said tuning means, control means connected with saidremote selector for rendering said motor actuated means operative, arotatable dialing means rotatable through a predetermined angleaccording to the desired station associated with the selector forremotely determining the operation of said control means at a desiredstation position of said tuning means, and means associated with thelatter adapted to cooperate with said control means for automaticallyrendering said motor actuated varying means inoperative at said posltion, said varying means being rendered operative only after saidcontrol means operation position has been determined by the dialingmeans.

5. In combination, a radio receiver, a station selector remote from thereceiver, means including a variable reactance for tuning the set to adesired station, an electrically actuated means for varying said tuningmeans, control means connected with said remote selector for renderingsaid actuated means operative, a rotatable dialing means associated withthe selector for remotely determining the operation of said controlmeans at a desired station position of said tuning means, a stop forlimiting the angular rotation of said dialing means, and replaceablestops mounted on the tuning means adapted to cooperate with said controlmeans for rendering the electrically actuated varying means inoperativeat said station position, said varying means being rendered operativeafter said controP means operation position has been determined by thedialing means.

6.111 combination, a radio receiver, adjustable reactance means fortuning the receiver to a desired station, an electrically operated meansfor varying the tuning means, control means for said varying means, anda rotatable dialing means remote from said receiver connected toselectively actuate said control means for rendering said varying meansoperative, and replaceable stops on said tuning means adapted tocooperate with said control means for rendering said varying meansinoperative at predetermined dial points corresponding to said stops, atleast two of said stops being arranged to be angularly adjustable withreference to said tuning means.

7. The combination with the tuning elements of a radio receiving systemof a tuning shaft, a plurality of replaceable tripping members mountedon said shaft, a power means for driving said shaft, an intermittentlyactuated control including a switch for rendering said power meansoperative, and a remote station selector electrically connected to saidintermittently ac tuated control means for selectively positioning thesame in the path of a predetermined one of said members.

8. The combination with the tuning shaft of a radio receiver, of anindicating drum mounted on said shaft, a plurality of trip membersmounted on said drum at different station positions, at least two ofsaid trip members being angularly adjustable about the periphery of saiddrum, an electrically actuated means for driving said shaft, a controlmember for said driving means including an element movable into thepaths of said trip members, a station selector dial electricallyconnected with said driving means and control member for selectivelycaus ing the advancement of said movable element into the path of apredetermined one of said trip members and means for limiting the extentof motion of said dial to a predetermined amount.

9. In combination, in a radio receiver, a rotatable tuning shaft, aplurality of adjustable members associated therewith in diiferentstation positions, means for actuating said shaft, means including amember mounted for longitudinal and angular movement for controlling theoperation of said shaft actuating means, and additional means remotefrom the receiver for selectively positioning the last mentioned memberin the path of a predetermined one of said adjustable members to rendersaid shaft actuating means inoperative at a position of the tuning shaftcorresponding to one of said eta-- tion positions.

10. In combination, in a radio receiver, a retatable tuning shaft, aplurality of adjustable members associated therewith in differentstation positions, means for actuating said shaft, means, including atripping member, for controlling the operation of said shaft actuatingmeans, and additional means remote from the receiver for selectivelypositioning said tripping member in the path of a predetermined one ofsaid adjustable members to render said shaft actuating means inoperativeat a position of the tuning shaft corresponding to the desired stationposition.

11. Tuning apparatus for radio receivers and the like comprising amember associated with the said radio receiver so that movement thereofwill cause a tuning element of said receiv r to be adjusted, a pluralityof position determining elements arranged to move as said member ismoved, each of said position determining elements having a part thereofadapted to follow a path which is different from the path followed bythe corresponding part of each of the other elements, a member movableprogressively into each of said paths, means for controlling theprogressive movement of said member whereby it may be stopped in apredetermined one of said paths, mechanism for causing movement of thefirst mentioned member, and mechanism actuated by said member movableprogressively into said paths for causing the first mentioned member tostop at a predetermined position.

12. Tuning apparatus for radio receivers and the like comprising arotatable element associated with a tuner of the said radio receiver formovement therewith, a plurality of members arranged to rotate with saidelement, each of said members being provided with a contact area, saidareas being located so that each area follows a path which is parallelto the paths of the other areas, means movable progressively into eachof said paths, mechanism for controlling the progressive movement ofsaid means whereby it may be stopped in a predetermined one of saidpaths, mechanism for rotating said element, and mechanism actuated bysaid means for causing said element to stop at a predetermined position.

13. Tuning apparatus for radio receivers and the like comprising meansassociated with the said radio receiver so that movement thereof willadjust a tuning element of said receiver, a plufollowed by the actuatorsof the other elements, a :u"

member movable progressively into each of said paths, a rack and pawlmechanism for advancing said member progressively whereby it may bestopped in a predetermined one of said paths,

mechanism for causing movement of the first i mentioned means, andmechanism actuated by said member for causing the first mentioned meansto stop at a predetermined position.

14. Tuning apparatus for radio receivers and the like comprising atuning dial, a plurality of members secured to said dial for movementtherewith, each of said members having a projection located so that itfollows a path which is different from the path followed by theprojection on each of the other members, an element movableprogressively into each of said paths, manually operable means forcontrolling the progressive movement of said member whereby it may bestopped in a predetermined one of said paths, mechanism for rotatingsaid tuning dial, and mechanism actuated by said element when itcontacts with one of said projections for causing the tuning dial tostop at a predetermined position.

ERNEST A. ZADIG.

